1. Field of the Invention
This invention relates to the manufacture of cheese byproducts suitable for human consumption. This invention further relates to a method for processing cheese whey to produce a very low moisture content, inexpensive cheese filler which can be mixed with other cheeses.
2. Description of the Prior Art
The whey byproducts produced in the normal processing or manufacture of cheese are known to contain quantities of useful fats and proteins. Prior to this time, a number of processes have been developed to produce products suitable for both human and animal consumption by removing these fats and proteins from the whey byproducts before they are discarded.
In a number of well known processes a Ricotta cheese product is made by salting, heating and acidifying fresh whey in a cheese vat, skimming the floating precipitated cheese solids and drying the solids. However, cheese products made in this fashion are generally high moisture content cheese products not suitable for grating and/or use as a cheese filler. Even prolonged drying of these products, to the point of spoilage, results in products having moisture contents too high for use as a grated cheese filler product. While of course the moisture content can eventually be reduced to a suitable level, this level is only reached after spoilage and wastage of at least a portion of the cheese product.
For example, Sanders, Cheese Varieties and Descriptions, U.S. Department of Agriculture Handbook No. 54, 1953 teaches a process for making a Ricotta cheese product from 0.20% acidity whey by heating the whey to 200.degree.F., adding sour whey or other coagulant and removing the floating precipitated coagulated albumin by dipping with a perforated ladle or dipping cloth. After draining and/or pressing in cheesecloth lined hoops the product may be marketed as "fresh or moist Ricotta" having a moisture content of 68 to 73 percent. If the product is to be marketed as "dry Ricotta," the curd is further dried by pressing in perforated forms and drying in a curing room at 100.degree.F. or higher. This dry Ricotta has a moisture content of 60% which is more than twice as high as is suitable for a grated cheese filler product. If any effort is made to continue the drying to a low enough moisture content for a grated cheese product, the curd would spoil before an acceptable moisture content could be reached. The fact that this cheese product has such a high moisture content inherently results from the method of its manufacture which produces large curd particles entraining considerable moisture.
In still another example, Kosikowski, Cheese and Fermented Milk Foods, Cornell University, 1966, teaches that whole milk Ricotta cheese may be made by acidifying whole milk to pH 5.9-6.0, heating the milk to about 176.degree.F. to precipitate and coalesce the curd and recovering the curd by dipping. Any curd not precipitated by the initial acidification may be coagulated by subsequent acid additions. The resulting cheese product is "characterized by a high moisture content very similar to creamed cottage cheese"-- i.e., a moisture content in excess of about 72%. This high moisture content is attributable to the precipitating of the curd whereby large curd particles are formed notwithstanding that fine curd flakes initiate the precipitation. The particle size is in part caused by the effort to effect total curd precipitation by a single massive acid addition. However, as a practical matter, not all of the curd will precipitate at once and therefore subsequent small acid additions are employed to coagulate the remaining curd.
Dry Ricotta, suitable for grating, may be made from high moisture cheese by pressing the curd into molds for 24 hours at room temperature and curing the cheese for several months at 50.degree.-60.degree.F. or for 4 weeks at 70.degree.F. However, during this curing period spoilage occurs and it is necessary to clean the cheese surface from time to time and to discard the spoiled waste.
Other processes are known for manufacturing by-products from cheese whey. For example, U.S. Pat. No. 3,252,961 to Rodgers et al., describes a process for recovering proteins from whey in which an anionic polyelectrolyte flocculating agent is added to a whey solution containing a whey protein precipitate. The product produced by this process is whey protein curd having a quasicrystalline structure. While this product has a high content of protein, it cannot be directly used as a human foodstuff, because such cheese-whey-byproducts do not have a particularly pleasing flavor or aroma.